Thermal Analysis of Cast Resin Dry-Type Transformers Based on Finite Element Method

Cast resin dry-type transformers have been widely used in areas where fire risk and oil leakages are unacceptable, such as hospitals, airports and commercial areas. Compared to oil-immersed transformers, cast resin transformers have poor thermal cooling performances due to the low thermal conductivity of resins. Temperature is one of the key factors affecting the lifetime of the insulation system. Therefore, it is important to analyze the temperature distribution of cast resin transformers as a part of the design to ensure reliable operation. This paper develops a thermal model based on the finite element method to simulate the temperature distribution of cast resin transformers. The thermal model is first validated by comparing the simulation results with test data. Then it investigates the influence of critical parameters including resin material properties and environmental conditions on the average winding temperature and hot-spot temperature.